Location-based services (LBS) are offered by some mobile terminal networks as a way to send custom advertising and other information to mobile terminal users based on their current location. Location-based services are provided through positioning methods which can quickly provide accurate location information of mobile communication terminals, such as mobile phones and PDAs, to users of the mobile communication terminals. Examples of the positioning methods include navigation satellite-based positioning and terrestrial-based positioning. The navigation satellite-based positioning uses pseudorange, accumulated carrier phase, Doppler shift and the like which are obtained through satellites, such as GPS, GLONASS or Galileo. The terrestrial-based positioning uses the time of arrival (TOA), time difference of arrival (TDOA), angle of arrival (AOA), or signal strength (SS) of a signal which are obtained through network infrastructure for mobile telecommunications.
In the event the terrestrial-based positioning is employed to provide the location-based services in urban centers, non-line-of-sight (NLOS) may occur due to obstacles, such as buildings. In order to remove the non-line-of-sight and provide a more accurate location-based service, a spatiotemporal error contained in the location information of a mobile communication terminal needs to be calculated and corrected. For this purpose, correction receivers are installed at several known locations, or receivers are mounted on vehicles to receive location information through GPS.